SV-POW! … All sauropod vertebrae, except when we're talking about Open Access

Bifid Brachiosaurs, Batman!

September 6, 2009

These are the days of miracle and wonder, especially for all you right-minded people out there who are lovers of fine brachiosaurs. I heard yesterday evening about a new paper in Proceedings of the Royal Society B: You and Li’s (2009, duh) description of a new brachiosaur, the first one known from the Cretaceous of Asia: Qiaowanlong kangxii. Best of all, it’s based primarily on vertebral material:

Brachiosaur aficionados will be gazing slack-jawed at parts d, f and h of this figure (the anterior, posterior and dorsal views of C9), which clearly show that the neural spines of the new taxon are bifid (i.e. have two peaks side by side and a trough between them) — just like the cervical neural spines of flagellicaudatans (diplodocids and dicraeosaurs) and camarasaurs. And mamenchisaurs. And some titanosaurs. And Erketu. Finding this feature yet again — apparently independently evolved in brachiosaurs — makes it about the most plastic character in the matrix. Very exciting.

That is, it’s exciting if this really is a brachiosaurid. Now as it happens, Matt was one of the reviewers for this paper (and by the way did an amazingly professional job of not telling me about it until it came out, the git). He’s told me in email that he’s satisfied that Qiaowanlong really is a brachiosaur, and I hesitate to question that identification given that (A) unlike the authors I’ve never seen the material, and (B) unlike Matt, I’ve spent most of my brachiosaur-presacral quality time with dorsals rather than cervicals. But, with that caveat, I’m not sure that a compelling case has yet been made for a brachiosaurian identity.

The authors cite three characters in support of a brachiosaurid identity:

The most persuasive is the deeply excavated cervical neural spines.

Next is a transition in neural spine height: this is quite abrupt in “Brachiosaurus” brancai between cervicals 6 and 7, and also in Sauroposeidon — presumably also between C6 and C7, but that can’t be known for sure, since it’s only the assumption that this is the case that led to the identification of the four preserved Sauroposeidon cervicals as C5-C8 in the first place. In Qiaowanlong, this transition is “much less pronounced”, with spines increasing in height by only 25% rather then 100% in the other taxa — and occurs between C8 and C9. All in all, not really very similar to the condition in “B.” brancai.

The final character supporting the brachiosaurid identity of Qiaowanlong is the absence of an anterior centrodiapophyseal lamina. As the authors point out, though, this lamina does exist in “B.” brancai and is absent only in Sauroposeidon; so if this is evidence of anything, it’s a synapomorphy of a clade uniting Qiaowanlong and Sauroposeidon to the absence of other brachiosaurs — something that seems very unlikely given the proportions of the vertebrae.

Putting it all together, there seems to be only one convincing brachiosaur character cited; and that stands against several non-brachiosaur characters, most obviously the bifurcation of the neural spine and the low Elongation Index (centrum length divided by cotyle height) but also by a few other characters that are not discussed in the paper. For example, Matt has previously noted that in brachiosaur cervicals, the diapophyses are more anteriorly positioned than the parapophyses whereas in diplodocids the opposite is the case: as shown in fig 2(b) above, C6 at least of Qiaowanlong resembles diplodocids in this respect.

To try to get more of a handle on this, I put together a comparative figure of the 8th and 9th cervicals of various sauropods:

8th/9th cervicals vertebrae of various sauropods, scaled to the same centrum length. From top to bottom and left to right: "Brachiosaurus" brancai, Sauroposeidon; Qiaowanlong, Diplodocus; Haplocanthosaurus, Camarasaurus. Six sauropod vertebrae for the price of one!

Based on overall proportions, I don’t find it intuitively obvious that the Qiaowanlong (middle row, left) more closely resembles the brachiosaurs (top row) than it does the other three.

What does all this mean? Probably nothing: most likely there are further reasons for the brachiosaurid identification of the new taxon, and lack of space prevented their explanation and illustration. We can hope that the authors, having placed an initial brief description in Proc. B, will follow it up with a more comprehensive description and analysis in a journal that does not impose such tight length restrictions. But for now at least, my feeling is that the case for a bifid brachiosaur has yet to be made.

Moving on … Qiaowanlong is also represented by some nice appendicular material: the entire right side of the pelvis (ilium, ischium and pubis). The ilium certainly looks brachiosaury, so that is another bit of support for the systematic hypothesis, but the proportions of the pelvic bones are very odd:

Right pelvis of "Brachiosaurus" brancai (left), based on composite of Janensch's (1961) figures, and Qiaowanlong (from You and Li 2009: fig. 3a). Scaled to same ilium length.

You and Li (2009) describe their pelvis as having a “much reduced ischium”, but as is apparent by comparison with the pelvis of “Brachiosaurus” brancai, the ischium is in reasonable proportion to the ilium, and the oddity is more that the pubis is enormous. So much so that it makes me feel a little ill looking at it, and it makes me wonder how certain it is that all three of these bones are from the same individual — sadly, the paper doesn’t discuss the association of the material.

[Not to flog a dead horse, but this kind of omission shows once more the perils of publishing new taxa in general-interest journals such as Proc. B that impose draconian length limits. This paper just creeps onto page 7, and I simply don’t believe that it’s possible to do anything like justice to the description of a new taxon in that little space, especially when there is also geography, geology, phylogeny and discussion to be got through. I don’t want to go all This Is How To Do It, but I can’t help remembering that Darren and I took 18 pages, nearly three times as long, to describe the single partial vertebra that is Xenoposeidon (Taylor and Naish 2007), and it’s not as though that paper wastes a lot of words. To give You and Li credit, they did squeeze in photos of a representative vertebra from all six cardinal directions, which is great; but only at the cost of the photos being too tiny to be much use. Please, folks: send your new taxon descriptions to a proper descriptive journal, not to a tabloid! </hobbyhorse>]

Back on the Dinosaur Mailing List, B tH asked how big Qiaowanlong was. According to the BBC, the authors say that “the dinosaur would have been a relatively small sauropod about 12m long, 3m high, and weighing perhaps 10 tonnes”. Can we confirm that? Well, the excellently comprehensive table of measurements in the paper gives centrum lengths, not counting the condyle, totalling 267 cm for the seven vertebrae C5-C11. Janensch (1950a:44) gave measurements for the corresponding vertebrae of “Brachiosaurus” brancai HMN SII totalling 577 cm, which is more than twice as long. If Qiaowanlong was 267/577 = 0.46 times as long as HMN SII, which Janensch (1950b:102) gave as 22.46 m, then it would have been 10.4 m long; it’s not obvious how the authors got the larger figure of 12 m unless they had reason to think the neck was proportionally shorter than in HMN SII. If Qiaowanlong was isometrically similar to HMN SII, then it was 0.46^3 = 0.99 0.099 times as heavy. Using my own in-press mass of 23337 kg for HMN SII, this would make Qiaowanlong only 2312 kg in mass — pretty pathetic for a sauropod.

That’s it for now. I’d be the first to admit that there’s an awful lot of speculation in this post based on relatively little published information. Hopefully You Hai-Lu will drop by and comment — I’ll be letting him know that I’ve posted this.

You, Hai-Lu, and Li, Da-Qing. 2009. The first well-preserved Early Cretaceous brachiosaurid dinosaur in Asia. Proceedings of the Royal Society B: Biological Sciences. doi: 10.1098/rspb.2009.1278.

And finally … two announcements!

Traumador the Tyrannosaur has asked us to point out that over on ART Evolved (the palaeo-art blog), the next big art gallery is to be sauropod themed. Details are on the site, so get over there and submit your sauropod art!

And Matt and I will shortly be teaming up with Andy Farke, the open-source paleontologist, on a new project where we plan to actually do some of this Shiny Digital Future that we keep on talking about. Andy will be announcing the details on Tuesday 8th September. Mark the date well! For now, I shall say no more …

18 Responses to “Bifid Brachiosaurs, Batman!”

How many other brachiosaur-grade macronarians were included in the analysis? What about the Cretaceous and Asian Jiutaisauruis, Fusuisaurus, Huanghetitan, Tangvayosaurus, Huabeisaurus, Daxiatitan, Dongbetitan, Dongyangosaurus, Baotianmansaurus, Erketu, Gobititan, Phuwiangosaurus or Pukyongosaurus?

Of the above, all that preserve presacral neural spines (Baotianmansaurus, Daxiatitan, Dongebetitan, Dongyangosaurus, Erketu, Huabeisaurus, Phuwiangosaurus) have them bifurcated. As does the always-included Euhelopus, of course. Really, it seems bifurcated neural spines were the norm for basal Asian titanosauriforms at least.

Honestly, with how many basal titanosauriform taxa are known, and how much analyses can change with the addition or subtraction of one OTU, I don’t think we can say anything is a brachiosaurid or not besides Brachiosaurus itself. Someone should just spend a few days plugging these taxa into whatever the newest Upchurch+Wilson matrix is. I would, but my knowledge of laminae is horrible.

What strikes me as especially bizarre about that pelvic girdle is that the proximal end of the pubis is proportionally almost identical in the second as it is the first–then it leads to the Distal End That Ate New York (or just for Mike, London).

Assuming it is part of the same specimen, are there any other dinosaurs known with such disproportionate pelvic elements?

Given that the pubis-ilium and pubis-ischium articulations are such close fits and the same sizes on both bones, I don’t particularly doubt the association of the pelvis.

Also Mike, I appreciate your dedication to open-access and long comprehensive descriptions. However, you have the luxury of not needing to find employment in the field. Publishing short-form articles in high-impact journals is absolutely necessary to get a job and get tenure at a research I university and/or major museums. This means publishing in journals such as Nature, Science, PNAS, and Proceedings B.

Right now, PLoS Biology is the only credible open access alternative to those journals, and so far it hasn’t been very friendly to paleo articles. I know of at least half a dozen quality paleo articles that were rejected from PLoS Biology for not being “of general interest” that subsequently got published in other high impact journals. PLoS One is a fantastic journal, but it will never have the impact of Nature and Science because it publishes so many articles. And I don’t mean *impact* just in terms of *impact factor* – job and tenure committees would still value articles in Science and Nature, etc. even if that statistic didn’t exist, principally because these journals are so selective (rightly or wrongly).

I wish we could all just publish long comprehensive papers in open access journals, but that simply isn’t reality right now for a beginning/young scientist trying to start a successful career. The best folks can do is publish *both* long and short articles in *both* open access journals and high-impact journals. At the same time, the new generation can work for cultural change when serving on hiring and tenure committees. But this will take time, and in the mean time, most scientists will still need to publish in places like Science and Nature to advance their career.

I don’t see why a short summary article can’t be in Nature or wherever, and then a long comprehensive article online elsewhere. Surely a subject accepted by Nature has been demonstrated to be “of general interest”. Actually, I don’t understand why Nature itself doesn’t have an online annex for long-enough versions of the articles. Surely they haven’t convinced themselves that their short form really is enough to do each topic justice?

Typos… grumble, grumble. Should read ‘the proximal end of the pubis is proportionally.’

Also, I can’t help but agree that short communications to Nature are fine (tolerable?) as long as a more detailed description is followed in the (hopefully not too distant) future. I know of a few specimens that are undergoing just that.

But at the same time, that’s obviously not always the case. Lots of complexities at hand, but I hope that over time we can work to at least help fix some of them.

Same: if you can’t get an ü, write ue. Also, all nouns are always capitalised in German: Teil (part), Lieferung (delivery).

Someone should just spend a few days plugging these taxa into whatever the newest Upchurch+Wilson matrix is. I would, but my knowledge of laminae is horrible.

1) Do it anyway.
2) Write a nice manuscript about it, and submit it for publication.
3) Suggest Mike and Matt as referees!

See? Simple.

How come you haven’t published anything yet? I’m your age and have 4 papers with 23 citations so far (and I’m working on the 5th, and at the same time on what could become part of the 5th or a separate 6th one…). If I had your encyclopedic knowledge of theropod phylogeny, I’d have been publishing for the last 9 years!!!

(I’m also amazed that you manage to keep up with the Asian sauropod discoveries. — BTW, you mistyped Dongbeisaurus.)

Actually, I don’t understand why Nature itself doesn’t have an online annex for long-enough versions of the articles.

It does, sort of. Several recent papers have had 90 to 100 pages of online supplementary information.

“1) Do it anyway.
2) Write a nice manuscript about it, and submit it for publication.
3) Suggest Mike and Matt as referees!

See? Simple.”

I tried step 1 once, with the Curry-Rogers matrix for titanosaurs, since it seemed impressively huge (364 characters). Then I came across a problem I’m sure you can relate to. Of the first 50 characters (all cranial)-
– five were only present in Rapetosaurus.
– seven were non-varying.
– three were correlated with other characters.
– one I didn’t see any difference between taxa marked 0 and 1.
– four I lacked the ability to verify for any taxa (thanks to a lack of firsthand examination and description in the literature).
– six I lacked the ability to verify in at least some taxa Curry-Rogers coded them as present or absent in.
– two contained codings which differed from other matrices, which I lacked the ability to confirm either way.
– at least six involved ratios or angles that were not explicitly stated (e.g. “feature x robust”), so would require me to measure every taxon to determine how she defined each state, assuming I’m measuring the exact same landmarks she did.

Now maybe that’s not representative of the entire matrix, maybe it would be different if I knew more about sauropods, and maybe Upchurch’s/Wilson’s are better. Though keep in mind these were all titanosaur skull characters, so it’s not like I had many taxa to check. The basic conclusion is one I’m sure you’ve learned as well- properly adding taxa to someone else’s matrix is almost as much work as creating your own matrix, and saving time by trusting the author leads to less assurance the data is correct.

“How come you haven’t published anything yet? I’m your age and have 4 papers with 23 citations so far (and I’m working on the 5th, and at the same time on what could become part of the 5th or a separate 6th one…). If I had your encyclopedic knowledge of theropod phylogeny, I’d have been publishing for the last 9 years!!!”

I know some SVPOW posters agree with you there! I am actually finishing up a manuscript with Nick Gardner at the moment, and have ideas for two future short papers I hope to submit this year too. The short answer to why it’s taken me so long is that I’m a perfectionist when it comes to these things, plus I’m easily distracted so keep jumping around the theropod tree on miniprojects. For instance, lately I had hesperornithine phylogeny distract me from finishing the paper with Nick.

“(I’m also amazed that you manage to keep up with the Asian sauropod discoveries. — BTW, you mistyped Dongbeisaurus.)”

Thanks! I wouldn’t say “keep up with” as much as “have all the descriptions as pdfs and quickly searched through them to find out which ones were Asian and Cretaceous.” ;)

Mickey, your last comment should be carved in forty-foot letters of fire on the side of Honest Bob’s School Of Cladistics. It’s a cautionary tale that everyone should be told, and one that far too few people seem to appreciate. I would almost go so far as to say that the most important benefit of doing a cladistic analysis is not getting the result but getting an insight into how arbitrary and fallible the scoring is, and also into how plastic the results can be — and generally how little they are to be trusted.

None of this is to knock cladistics, by the way: unlike Greg Paul and “anonymous” from the Tutorial 7 comments, I think it is by far the best mechanism we have right now for putting together credible phylogenetic hypotheses. But this is rather like saying that analysing form in past races is the best way of predicting who will win future races: it’s true, but it doesn’t by any means make the method infallible.

(Anyone who is inclined to accept cladistic results too trustingly should meditate for a while on how scientists and competent and careful as Upchurch and Wilson could recover such totally different positions for Euhelopus within Eusauropoda.)

For codings you can’t check on your own, write to people who can; if that doesn’t work (some people never reply to e-mails), either brutally score them as unknown and say so in the paper, or trust the authors and say so, too.

I’ve not had that problem much… the most impressive case is where the descriptions, sometimes the same people within 20 years, contradict themselves on how many fingers per hand the diplocaulid Diceratosaurus has (4 or 5). At the congress in Berlin this July, we were led through the collections, I found an open cabinet door, and behind it was the holotype of Diceratosaurus… it’s got five fairly nicely preserved fingers. In the meantime, I had written to Angela Milner, who is one of the people who have contradicted themselves in the literature; she still hasn’t replied except for saying she was busy and would get to it soon… The exact same problem exists for the diplocaulid Keraterpeton. I’ll write to Milner again; if she doesn’t reply, “four or five” will stay in the matrix and will be published mercilessly.

I am actually finishing up a manuscript with Nick Gardner at the moment, and have ideas for two future short papers I hope to submit this year too.